Recently, due to progresses made in optical communication techniques, communication is often made between information processing apparatuses by connecting the information processing apparatuses via an optical fiber cable and transmitting and receiving optical signals via the optical fiber cable. A laser optical module is used to output a laser beam from a laser light source to the optical fiber cable depending on transmitting information, and is normally provided with a laser safety circuit. The laser safety circuit is provided to control the output, so tat the intensity of the laser beam output from the laser optical module satisfies a laser safety standard.
Conventionally, the laser optical module is designed to primarily make the transmission by a single channel. For this reason, one laser safety circuit is provided within the laser optical module, in correspondence with the single channel.
However, due to increasing amount of information to be transmitted, it is expected that future laser optical modules will make the transmission by a plurality of channels. Hence, there are demands to develop a parallel optical module suited for the communication using the plurality of channels.
On the other hand, the intensity of the parallel transmission output of the laser beam is already prescribed by an international standard such as IEC, and such a laser safety standard must be satisfied from the point of view of safety. However, since the conventional laser optical module is designed to make the transmission by the single channel, only one laser safety circuit is provided. For this reason, when the conventional laser optical module is applied to the parallel optical module having a plurality of channels, there is a problem in that the output cannot be appropriately controlled to satisfy the laser safety standard. Consequently, there are demands to realize a parallel optical module which can make the transmission by the plurality of channels and simultaneously satisfy the laser safety standard related to the intensity of the parallel transmission output of the laser beam.